The vast majority ‒ 85 percent ‒ of tampons, cotton and sanitary products tested in a new Argentinian study contained glyphosate, the key ingredient in Monsanto's Roundup herbicide, ruled a likely carcinogen by the World Health Organization.

Meanwhile, 62 percent of the samples tested positive for AMPA, glyphosate's metabolite, according to the study, which was conducted by researchers at the Socio-Environmental Interaction Space (EMISA) of the University of La Plata in Argentina.

All of the raw and sterile cotton gauze analyzed in the study showed evidence of glyphosate, said Dr. Damian Marino, the study's head researcher.

“Eighty-five percent of all samples tested positive for glyphosate and 62 percent for AMPA, which is the environmental metabolite, but in the case of cotton and sterile cotton gauze the figure was 100 percent,” Marino told Télam news agency. An English translation of the Télam report can be found here. The products tested were acquired at local stores in Argentina.

“In terms of concentrations, what we saw is that in raw cotton AMPA dominates (39 parts per billion, or PPB, and 13 PPB of glyphosate), while the gauze is absent of AMPA, but contained glyphosate at 17 PPB.”

“The result of this research is very serious, when you use cotton or gauze to heal wounds or for personal hygiene uses, thinking they are sterilized products, and the results show that they are contaminated with a probably carcinogenic substance,” said Dr. Medardo Avila Vazquez, president of the congress.

“Most of the cotton production in the country is GM [genetically modified] cotton that is resistant to glyphosate. It is sprayed when the bud is open and the glyphosate is condensed and goes straight into the product,” Avila continued.

Marino said the original purpose of his research was not to test products for glyphosate, but to see how far the chemical can spread when aircraft sprayed an area, such as cropland.

“There is a basic premise in research that when we complete testing on out target we have to contrast it with something ‘clean,’ so we selected sterile gauze for medical use, found in pharmacies," he said.

“So we went and bought sterile gauze, opened the packages, analyzed and there was the huge surprise: We found glyphosate! Our first thought was that we had done something wrong, so we threw it all away and bought new gauze, analyzed them and again found glyphosate."

Argentina has had a tampon shortage in recent years based on the country's policies concerning imports and foreign currency, according to reports in January. Most of the nation's tampon imports come from Brazil, Miguel Ponce, head of the Chamber of Importers, told AP. Those tampons include American brands, such as OB and Kotex.

In 2014, 96 percent of cotton produced in the United States was genetically modified,according to the US Department of Agriculture.

Transnational agrochemical giant Monsanto's Roundup herbicide, of which glyphosate is the main ingredient, is sprayed over genetically modified crops ‒ which Monsanto also produces ‒ that are engineered to be resistant to the powerful chemical. Used the world over, glyphosate, which Monsanto first developed in 1974, is a broad-spectrum herbicide used to kill weeds, especially annual broadleaf weeds and grasses known to compete with commercial crops. GMO seeds have caused use of glyphosate to increase immenselysince the 1990s, according to US Geological Survey data.

In March, the International Agency for Research on Cancer (IARC), an arm of the World Health Organization, classified glyphosate as a "probable carcinogen," as opposed to its previous designation, a "possible carcinogen."

In the US, the herbicide has been considered safe since 2013, when Monsanto received approval from the US Environmental Protection Agency (EPA) for increased tolerance levels for glyphosate. In its original assessment, the federal regulator said glyphosate could be “used without unreasonable risks to people or the environment.”

Scientific studies have linked the chemicals in Monsanto's biocides to Parkinson's disease, Alzheimer’s disease, autism and cancer. Furthermore, as the most powerful multinational biotech corporation today, Monsanto has drawn the ire of farmers and consumers for its firm grip on the global food chain. The company's control and advancement of GMO seeds is of prime concern, as they symbolize the company's consolidation of agricultural processes.

The effects of biochemicals on wildlife, including pollinators such as honeybees and monarch butterflies, are also a point of concern. For instance, since 1990, about 970 million of the butterflies – 90 percent of the total population – have vanished across the United States, according to the Fish and Wildlife Service. At least part of the blame rests on the boom in Roundup use. The herbicide is marketed to farmers and homeowners as an effective method for eliminating plants like milkweed, so it's widely blamed for decimating the butterflies’ only source of food in the Midwest.

Two-thirds of European Union nations have requested allowance to ban GMO crops, pursuant to European Commission rules.